Receptor-Ligand Kinetics
The receptor-ligand kinetics is typically described by the chemical reaction:
\[R + L \rightleftharpoons RL\]where \(R\) is the receptor, \(L\) is the ligand, and \(RL\) is the ligand-receptor complex. The reaction is characterized by the on-rate constant \(k_{on}\) and the off-rate constant \(k_{off}\).
Association and Dissociation constants
At equilibrium, the rate of association is equal to the rate of dissociation:
\[k_{on}[R][L] = k_{off}[RL]\]The equilibrium association constant is defined as:
\[K_a = \frac{k_{on}}{k_{off}}\]and the dissociation constant \(K_d\) is its inverse. These constants are usually measured experimentally to describe the kinetics of the receptor-ligand interaction. A high \(K_a\) indicates a strong binding, while a high \(K_d\) indicates a weak binding (the inverse is true for \(K_d\)).
Experimental methods
The experimental methods used to investigate the kinetics of receptor-ligand interactions includes: ligand binding assays, crystallographic analysis, all atom MD simulations.
References
- Wikipedia
- Yao, Yongneng, et al. “Molecular mechanism of ligand recognition by NR3 subtype glutamate receptors.” The EMBO journal 27.15 (2008): 2158-2170.